Prepare a batch of 17 Beta-hydroxy-C19-steroid dehydrogenase from male guinea pig kidney according to our recently reported procedures (Endocrinology 95(3): 766-770, 1974, D. Stevenson and C.D. Kochakian). These isoenzymes will be separated and characterized by determination of amino acid composition, end group analysis, sulfhydryl content, partial end group sequencing, different partial hydrolyses to determine whether enzyme activity resides in smaller subunits.